The recent trend in dentistry is the use of prosthetic devices using non-gold containing alloys. Nickel and beryllium are two metals currently being used in place of gold as components of base metal castings. However, several reports have indicated that they may be considered to be possible health hazards. Preliminary in vitro investigation in our laboratory has demonstrated that the release on nickel and beryllium from prosthetic devices into simulated saliva is pH dependent. The dissolution data showed that a relatively high percent beryllium was released into salivary secretions. Emission spectroscopic analysis showed that the ratio of ions released was not similar to that in the original alloy. The data suggested that beryllium concentration was not uniform across the alloy, but rather enriched toward the surface of the alloy. Thus, the effective surface concentration of beryllium appears to be higher than the proposed set limit of 2 percent. The tissue response to the apparent increased surface concentration of beryllium may possibly be manifested in the adjacent gingival tissue and crevicular fluid. In this proposal, the influence of increased levels of beryllium on gingival fibroblast functions will be investigated in in vitro. These studies will provide baseline information to indicate the need to re-assess permissible and safe levels of beryllium in base metal castings.